1. Field of the Invention
The present invention relates to a semiconductor device and, more specifically, to a semiconductor device having a power semiconductor mounting board contained in a package.
2. Description of the Background Art
Semiconductor devices used for driving inverters of industrial equipment have various and many forms corresponding to the numbers of packages or switching elements such as an IGBT (Insulated Gate Bipolar Transistor), and the forms are denoted, for example, as 1in1, 2in1 or 7in1. Specifically, 1in1 denotes a semiconductor device having one switching element mounted on one package, and 2in1 denotes one having two switching elements mounted on one package, while 7in1 denotes a semiconductor device having a total of 7 switching elements, that is, 6 switching elements for a 3-phase inverter and one switching element for braking, mounted on one package.
Further, screw block terminals and pin terminals are attached to a semiconductor device, for connection to an external device or the like. A semiconductor device has such a structure that easily allows change in attachment position of such screw block terminal or pin terminal, in accordance with its form. Specifically, on a case member forming the package of a semiconductor device, wall-shaped fixing members extending from a sidewall portion are formed at a prescribed interval from each other, to provide a plurality of fixing positions along the periphery. A screw block terminal or a pin terminal is fixed by the fixing member at a prescribed position corresponding to its form. References disclosing general semiconductor devices having connection terminals for external connection include Japanese Patent Laying-Open Nos. 11-177259, 2002-314035 and 10-116961.
The conventional semiconductor, however, has the following problem. When the semiconductor device is connected to an external device, it is necessary to attach an external terminal such as a bus-bar, to a screw block terminal. Here, the bus-bar is attached to the screw block terminal, by inserting a screw to an opening of the bus-bar and by tightening the screw in a threaded hole formed in the screw block terminal. When the screw is tightened in the screw block terminal, however, the screw block terminal or the case member, on which the screw block terminal is fixed, may be damaged by the fastening stress. As a result, it is sometimes difficult to attain sufficient tightening torque and to securely attach the external terminal to the screw block terminal.